<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_流程控制</title>
</head>
<body>

<script>
    //1. 顺序结构
    console.log(1);
    console.log(2);
    console.log(3);
    //2. 分支结构
    /*let username= '';
    if (!username){// ！Boolean(username)
        alert('用户名不能为空');
    }else {
        alert('欢迎回归');
    }*/
    //3. 选择分支
    let gender =0;
    switch (gender){
        case 1:
            console.log('男');
            break;
        case 0:
            console.log('女');
            break;
        default:
            console.log('未知');
    }
    //4. 循环结构
    let names=['张三','李四','王五'];
    for (let i = 0; i < names.length; i++) {/* .length是属性*/
        console.log(names[i]);
    }
    console.log(i);
    /* 增强for循环 */
    for (let name of names){
        console.log(name);
    }
</script>
</body>
</html>